Polyferric sulfate (PFS) is a polymer made from ferric subsulfate, a compound having a molecular formula Fe4(OH)2(SO4)5. The molecular formula of polyferric sulfate is [Fe2(OH)n(SO4)3-n/2]m, where 0.5<n<1 and m=f(n).
Traditionally polyferric sulfate is used as inorganic flocculating agent. When compared with other kinds of flocculating agents polyferric sulfate has several advantages, such as relatively low dosage, adapt to be used in wide pH range, high removal ratio for impurities (turbidity, COD, suspended matters, etc.), low concentration of residues, high flocculating speed, good de-colorization effect, etc. At present polyferric sulfate is widely used for purifying treatment of industrial waste water, urban sewage, and domestic water. When polyferric sulfate is hydrolyzed in water it will produce poly-nuclear hydroxyl complex, which has a strong absorption for colloidal particles in a variety of water body and makes the particles aggregate and flocculate through bonding, bridging, and cross-linking.
In recent years, on the basis of flocculants such as poly-silicate and poly-ferric sulfate, researchers developed the following new inorganic or organic polymer composite flocculants which contains polymeric ferric salt composite: poly-silicate ferric composite salts, such as poly ferric silicate chloride (PFSC), polymeric ferric sulfate silicate (PFSS), and polysilicate ferric aluminum sulfate (PAFSC); polyphosphate ferric composite salts, such as polyphosphate ferric sulfate (PPFS); poly aluminum-ferric composite salts, such as polymeric aluminum ferric phosphate (PAFP); flocculants containing poly-ferric chloride sulfate (PFCS); flocculants containing co-polymeric ferric salts, such as poly-aluminum ferric chloride (PAFC); organic polymeric flocculants, such as organic cationic polymeric flocculants-DMC copolymer, CTS-AM-DMC strong cationic natural polmer (chitosan(CTS)-methacryloyl-oxyethyl trimethyl ammonium chloride (DMC)-acrylamide (AM) strong cationic natural polymer) flocculants and their analogue; organic/inorganic polymer composite flocculants, such as CAF (a kind of organic/inorganic polymer composite flocculants made from chitosan, polyaluminum, and ferric chloride) and its analogue.
Compared with ferric subsulfate and polyferric sulfate (PFS), the above mentioned new types of flocculants have higher molecular weights, stronger ability for adsorption and bonding, and better ability for removing turbidity, COD and BOD. For example, when treating sewage the dosage of polymeric ferric sulfate silicate (PFSS) is one-third less than that of polyferric sulfate. It was reported that when treating a slurry of coal, the dosing amount of an inorganic flocculants polyaluminum chloride is more than 1.0KG/per ton of coal when used alone, and the dosing amount of organic flocculants polyacrylamide is a bit less than 0.1KG/per ton of coal when used alone. However when both are used the dosing amount is much less due to their combination.
Although the use of the above substances as flocculants is well known up to the present no one has tried to make use of the properties of these substances in the medical field. That is to make pathological tissues in living bodies dehydrated, atrophied and eventually eliminated.
Therefore, there is a need to provide a novel pharmaceutical composition for dehydrating, atrophying and eliminating pathological tissues.